Table 6.82—DRM_Ellipse

Property

Description

Superclass

·         <DRM Surface Geometry>

Class

·         <DRM Ellipse>

Subclass

·         none

Definition

An instance of this DRM class specifies a closed plane curve such that for each point on the curve, the sum of the point's distances from two fixed points (called the foci) is a constant. The <DRM Location> component specifies the centre of an instance.

The major axis is the line passing through the foci. The direction of the major axis is specified by the component <DRM Reference Vector> with vector_type = MAJOR_AXIS.

The minor axis is the line that passes through the centre and is perpendicular to the major axis. The direction of the minor axis is specified by the component <DRM Reference Vector> with vector_type = MINOR_AXIS.

Example(s)

·         The physical extent of certain underwater acoustic phenomena are best described by oval surface geometries in some cases (and by <DRM Elliptic Cylinder> <DRM Volume Geometry> in others.

Inherited field elements

field_name

range

Field_Data_Type

none

 

 

Field elements

field_name

range

Field_Data_Type

major_axis_length1

≥ 0,0

Long_Float

minor_axis_length2

≥ 0,0

Long_Float

Associated to (one-way) (inherited)

·         none

Associated to (one-way)

·         none

Associated by (one-way) (inherited)

·         none

Associated by (one-way)

·         none

Associated with (two-way) (inherited)

·         none

Associated with (two-way)

·         zero or one <DRM Geometry Node>3

Composed of (two-way) (inherited)

·         zero or more {ordered} <DRM Attribute Set Index>

·         zero or one <DRM Classification Data>

·         zero or more {ordered} <DRM Colour>s

·         zero or more {ordered} <DRM Image Mapping Function>s

·         zero or one <DRM Light Rendering Properties>

·         zero or one <DRM Presentation Domain>

·         zero or more <DRM Property Table>s

·         zero or more <DRM Property Table Reference>s

·         zero or more <DRM Property Value>s

·         zero or one ,DRM Rendering Priority Level>

·         zero or one <DRM Rendering Properties>

·         zero or more <DRM Tack Point>s

·         zero or one <DRM Union Of Primitive Geometry>

Composed of (two-way)

·         one <DRM Location>4

·         exactly two <DRM Reference Vector>s5

Composed of (two-way metadata) (inherited)

·         zero or one DRM_Time_Constraints_Data

Composed of (two-way metadata)

·         none

Component of (two-way) (inherited)

·         one or more <DRM Union Of Primitive Geometry>s

Component of (two-way)

·         none

Constraints

·         Colour mapping restrictions

·         Continuous LOD restrictions

·         Image mapping functions and texture coordinates

·         No attribute conflicts

·         Non-crossing aggregations

·         Non-crossing associations

·         Non-cyclic aggregations

·         Precedence of Attributre Set Index

Notes

1 In metres.

2 In metres.

3 Corresponds to the centre of the <DRM Ellipse>.

4 The location of the centre of the <DRM Ellipse>.

5 Elliptic cross section axes. The first component <Reference Vector> specifies the major axis direction with type = MAJOR_AXIS. The second component <Reference Vector> specifies the major  axis direction with type =MINOR_AXIS.

Class diagram

<DRM Ellipse>